Field of the Invention
The invention relates to a contact spring for an electrical bush contact, having a bottom spring with a boxlike housing as a spring arm base, two wide sides and two narrow sides each, a connection part integrally adjoining the spring arm base on one end, and resilient contact tongues angled relative to one another, defining an insertion funnel and formed onto the two wide sides of the opposite end of the spring arm base, the tongues touch one another in the position of repose, and having a top spring form-lockingly held on the bottom spring, the top spring encloses the spring arm base of the bottom spring on four sides and urges the contact tongues of the bottom spring toward one another with spring buckles disposed on the wide sides. A form-locking connection is one which connects two elements together due to the shape of the elements themselves, as opposed to a force-locking connection, which locks the elements together by force external to the elements.
Such contact springs are known in the prior art. For instance, German Utility Model DE 92 02 365 U1 describes a contact spring which is preferentially used widely as a plug connector in automotive engineering. The top spring serves the purpose primarily of increasing the contact force of the contact spring and, by forming detent tongues, of enabling releasable locking of the contact spring to an insulating housing.
Another structure for mutual locking of the top spring to the bottom spring is known from German Patent DE 32 48 078 C2. The spring arm base of the bottom spring provided in that patent is boxlike in cross section and has integrally formed-on top parts bent over by 90.degree. on upper edges of side walls. A boxlike top spring is fitted over the assembly and engages a recess in the top part of the bottom spring from behind through the use of a detent tongue.
In practically all of the contact assemblies with flat spring contacts, various problems arise. Along with the lack of the requisite contact security and a highly conductive electrical connection, problems can result from inadequate heat dissipation, excessive plugging forces and mechanical damage from inadequate protection of the contact assembly.
In order to eliminate those disadvantages, various options have been utilized, such as a floating spring construction or longer spring travel with longer spring legs, or increasing the contact normal force along with high plugging forces for inserting counterpart contacts, or using expensive materials with improved conductivity.
All of the contact structures with flat spring contacts known thus far offer only partial solutions for what are quite complex needs.